These Egyptian bayonets are like Romanian AKM I models. You can not find two same bayonets. I have more than 30 of them in collection and all have different blade points, handle color, hole on blade or something else...

Mr. B I go with they had quality control issues. Also, I agree that the "black: handles are indeed a blue-black.
Somewhere I have a panel that shows different colors of "black" from the automotive industry. These include blue-black, red-black and green-black (a friend of mine had a green-black Mercedes) as will as what they call true black. MDI

Maybe this will help explain/resolve the Blue vs Black controversy. Mike

There is no true black color! Black is the total absence or total absorption of light. Visible color is the reflection or refraction of light. This spectrum can be broken down to the Primary colors we visually perceive: Red-Green-Blue. All the other colors we see are combinations of these colors. They can be further broken down to the seven colors of the rainbow or prismatic refraction. This includes: Red-Orange-Yellow-Green-Blue-Indigo-Violet.

Black can be defined as the visual impression experienced when no visible light reaches the eye. Pigments or dyes that absorb light rather than reflect it back to the eye "look black". A black pigment can, however, result from a combination of several pigments that collectively absorb all colors. If appropriate proportions of three primary pigments are mixed, the result reflects so little light as to be called "black".

When formulating and molding synthetic material the Egyptians use a high percentage of Indigo in the dye mix to achieve "Black". The inconsistencies in dyes and the amounts used between batches and/or poor quality control results in various shades of "blue". The "Blue", (Indigo), is always there, but in varying amounts. This plus the various light sources under which they are viewed make the visual differences.

To verify the actual color of these components a Spectrometer can be used to determine the amount / percentage of the Indigo in the mix. It is in the spectrum between 420 to 450 nanometers in wavelength.

The dark blue can be difficult to detect under normal indoor lighting. Use intense white light and look at different angles. It also helps to have an East German or Yugo black next to it to compare. It took me several years to find a light blue/grey one that was very obvious to the naked eye under normal lighting. I ended up keeping 7 to display from almost black to light blue. mine end up looking like Trombi's pictured above. Mike

This is what to look for under high intensity photo lamps and also some camera flashes. a lot depends on the light and viewing angles. There is nothing blue in the room this was taken in, white walls, ceiling and brown carpet. M.